The present disclosure relates to an imaging lens that has a focusing function and is suitably used in an electronic camera such as a digital video camcorder and a digital still camera. The present disclosure also relates to an image pickup apparatus that uses such an imaging lens.
Recently, a digital video camcorder, a digital still camera, etc. that use a solid-state image pickup device such as a CCD (Charge Coupled Device) and a CMOS (Complementary Metal-Oxide Semiconductor) have been rapidly in wide spread use. With the spread of such digital cameras etc., a demand has been increased for a high-performance imaging lens that has superior portability and is suitable for high pixel density. Moreover, recent needs are various, which can be seen from some users requiring not only a zoom lens but also a single-focus lens that has a fixed focal length.
As a need for the single-focus lens, the single-focus lens is expected to have a large aperture ratio having an open F number of about F2, compact size, and high performance. Moreover, the single-focus lens is expected to be capable of shooting an object at an infinite distance to an object in proximity. As such an imaging lens, for example, lenses disclosed in Japanese Unexamined Patent Application Publication Nos. 2011-64919 (JP2011-64919A) and 2012-123340 (JP2012-123340A) are known. The imaging lens disclosed in JP2011-64919A has a floating mechanism that allows two lenses to travel during focusing operation, and has a half angle of view of about 25 degrees, an open F number of around 2.8, and maximum magnification of about ½. The imaging lens disclosed in JP2012-123340A has two shooting modes between which a distance of an object that is allowed to be shot is different, and has a half angle of view of about 25 degrees, an open F number of around 2.8, and maximum magnification of about ¼.